The Labor Department said Tuesday that the consumer price index rose 0.2 percent in March, after scant 0.1 percent increases in the previous two months. Prices have risen just 1.5 percent year over year. That remains well below the Federal Reserve's 2 percent target for inflation.

Excluding the volatile food and energy categories, core prices increased 0.2 percent in March and 1.7 percent in the past year.

The Fed is now trying to unwind some of that stimulus. It plans to buy $55 billion in bonds this month, down from $85 billion in March of last year. The bond purchases have been intended to lower long-term rates, which can spur borrowing and spending.

Despite scaling back its purchases, Fed officials have expressed concern about inflation running below their target. As a result, the Fed is prepared to hold shorter-term rates near zero even if unemployment falls by roughly a percentage point from its current level of 6.7 percent. This suggests that the Fed might not raise short-term rates until the middle of 2015.